April 26, 2011 -- Not knowing enough about basic health can be deadly for people with heart failure, a new study finds.

The study shows that nearly one in five people with heart failure have low health literacy, making them more than twice as likely to die as a result of their condition. According to the Institute of Medicine, health literacy is the degree to which a person can obtain, process, and understand basic health information and services needed to make appropriate health decisions.

The study appears in the Journal of the American Medical Association (JAMA).

Heart failure occurs when the heart's pumping chambers are not able to circulate blood efficiently enough to meet the body's needs. This is a complex condition and treatment typically involves a combination of medications, lifestyle changes, and sometimes surgery. Successful management requires ongoing, meticulous self-monitoring by the patient.

“Although patients with heart failure are frequently hospitalized, much care for heart failure is performed on a daily basis by individual patients outside of the hospital," researcher Pamela N. Peterson, MD, MSPH, of the Denver Health Medical Center, and colleagues write in JAMA. "This self-care requires integration and application of knowledge and skills. Therefore, an adequate level of health literacy is likely critical."

Lack of Health Knowledge Deadly

In the study, researchers looked at the relationship between health literacy and outcome in 1,547 patients with heart failure. The participants were all part of a managed care organization, were surveyed between 2001 and 2008, and followed for an average of about a year.

Health literacy was determined based on the participants' responses to the following three screening questions:

How often do you have someone help you read hospital materials?

How often do you have problems learning about your medical condition because of difficulty reading hospital materials?

How confident are you filling out forms by yourself?

The results showed that 17.5% of the participants had low health literacy. Those with low health literacy tended to be older and of lower socioeconomic status. They also were less likely to have a high school education and had higher rates of coexisting illnesses, like diabetes, high blood pressure, or stroke.

Researchers also found that 17.6% of those in the low health literacy group died as a result of heart failure during the follow-up period, compared with 6.3% of those with adequate health literacy.

Even after adjusting for other risk factors, such as age, heart pumping ability, and coexisting illnesses, low health literacy remained an independent risk factor for heart failure death.

Researchers say that the results show that even among people with health insurance and access to health care, such as in this study, low health literacy is linked to a higher rate of mortality. They say routine screening of health literacy may help identify people at risk.